Electrothermal starting carburetor



Oct. 1, 1929. c. L. BRISTOL 1,730,115

ELECTROTHERMAL STARTING CARBURETOR Original Filed June 5, 1926 j i lfl do 6 attorney ;v

I Patented Oct. 1, 1.92 9 v PATENT; OFFICE cnns'rnn L. nnrsron, or nnnim, onxo amc'rnornnnmar. gramme caanuamoa Application flle'd June 5, 1926, Serial No. 113,029. Renewed larch 1, 1929.

This invention relates to priming or starting'devices for internal combustion engines, especially motor vehicle engines, and particularly to means for supplying a gaseous explosive mixture to such engines.

Many attempts have heretofore been made to provide priming or starting devices of the general character to which this invention relates, but these, for the most part, have failed,

10 for one reason or another, to be efiicient and practical. i In order to effectively start an internal combustion engine .when cold, especially in winter weather, it is necessary to supply to the cylinders a non-condensing rich mixture of fuel vapor and air. It is not ordinarily suflicient, as-heretofore proposed by many, to inject liquid fuel into the cylinders or intake manifold. Neither can the best results be obtained by vaporizing the fuel and immediately allowing the undiluted vapor to come into contact with cold surfaces, on which it will quickly condense. I I

Prior investigators have heretofore proposed to supply liquid fuel to a heating device and then conduct the vaporized fuel from such heating device to the engine. Suchinvestigators have, however, for the most part, lost sight of the fact that the vaporization of the fuel in the heating device generates a very appreciable back pressure, which would in many cases, shut off the flow of liquid fuel to the heating device, and thus seriously reduce the supply of vapor at the very moment when it is most needed.

' I have discovered thatin order to effectively supply an abundant flow of explosive mixture to the engine at starting, it is necessary not only to employ a heating device, but also 40 to provide a pump for positively forcing the fuel intoand through the heating device, so as to overcome the back pressure above referred to, and maintain a continuous stream of fuel. v

Furthermore, I find that,fby providing means for confining the pressure due to the vaporization of the fuel, and preventing it from escaping backwardly in the direction from which the liquid fuel came, I can utilize such pressure to force the vaporized fuel out of the heatin device into the engine. Thus the pressure ue to the vaporization and superheating' of the fuel in the heating device serves to cause a positive flow of gaseous mixture into the engine, entirely inde endent of the suction of the engine, or even 0 the pump. This feature is especially advantageous in cold weather, when the engine is stiff, and 7 when it is frequently im ossible to rotate it fastenough to produce t e suction necessary go to draw in an adequate supply of fuel. I also propose to prevent the condensation 1 of the vaporized fuel issuing from the heating device by mixing the vapor with air, as fast as it issues, thus producing a carbureted 55 or explosive mixture which has the properties of a permanent gas, and from which the fuel particles will not readily condense when they'come into contact with the cold walls of the engine. (0 Electric heating devices for use in apparatus of the above character have been heretofore proposed, but in many cases, the designers appear to have failed to grasp the principles on which economy and efficiency 76 of-such a device should be founded. I find that, in order to conserve time and electrical energy, it is necessary to substantially isolate the heating element and fuel from any surrounding masses of metal or other material, so that no heat can be transferred from such element or fuel by conduction. In this way, all of the heat generated is available for vaporizing and superheating the fuel.

One of the important features of the in-. vention consists further in the provision of a speciallydesigned heating device, this device comprising a small tube of electrically conducting material, through which tube the fuel is'led, while an electric current is also passed through the. tube, thus heating the same and vaporizing the fuel.

In addition to the improved heating element, the present invention seeksto provide the im roved air mixing or carbureting device a ove referred to, and an im roved pumping mechanism for positively orcing the fuel into and through the heating devic.

In order that the invention may be readily understood, reference is bad to the accomof a pump either manual or power operated,"

may be employed, I prefer, as a matter of convenience and efliciency, to employ an electro-magnet-ically operated pump. In the embodiment shown in the drawing, this comprises a cylindrical casing 1, connected with 'upper and lower heads 2 and 3, all preferably being of magnetic material, and enclosing an insulating spool 4 on which is wound a bobbin of insulated wire 5, constituting a solenoid. This solenoid is provided with a to reciprocate in a pocket or-recess formed From theabove, it will beseen that when movable core '6, which preferably operates vertically, as shown. To the lower end of this core is rigidly secured a disc 7, which constitutes the piston of the pump. This piston snugly fits andreciprocates within the upper ortion of a tube 8, preferably formed of rass or the like, and having a bore which constitutes" the cylinder of the pump. This tube '8 is threaded at its upper end into a similarly threaded boss 9, formed. on the' lower head 3.

The lower part of the tube 8 is bored out to somewhat larger diameter-than the upper part, so as to form a shoulder 8 between the two bores. -Fitting within the larger bore and seated against the shoulder 8 is a cylindrical block 10, which constitutes the head of the pump. This block has a laterally extending port 11, which communicates with a pipe line 12, leading from the fuelreservoir (which may be either at a higher or lower level than the pump). The port 11 opens upwardly into the pump barrel and is controlled by means of a downwardly closin .ballcheck valve 13. ,This constitutesthe i et valve of the pump. The outlet from the pump is by way of a port 14, formed inthe block 10, and controlled by 'an upwardly closing ball check valve 15, which 15 confined to its place by a wire netting or other suitable cage 16. In a central socket in the upper face of the block 10, above'the ball 13, is screwed a plug 17, having a central opening or port through which liquid flowing past the checkvalve'13 passes intothe pump. bar-' rel. When the pump is idle and in its normal position, the port in the plug-17 is closed by means of a cone-shaped valve 18, mounted in the lower end of the core 6 and urged downardly by means of a light helical spring 19, mounted above the same. Thus, the valve 18 is held to its seat by this spring, and normally serves to shut off communication between the pipe 12 and the interior of. the

of is a sleeve or lining 21 of magnetic material. The purpose of this will hereinafter appear. Set into this sleeve at a point slight- 1y below the block-10 in a disc or plate 22, also of magnetic material, and carried by this plateand depending centrally in the sleeve 21 is a cylindrical bar or core 23, of magnetic material.

My improved heating element consists of an electrically conducting tube of small bore, preferably formed of some relatively high resistance material suchas nichrome; alloy.

end of the tube 8. This plug carries a de-,

pending hollow boss 29, into the lower end of which is threaded one end of a tube or conduit 27, which is then bent laterally and extends, as indicated at 28, to the engine,

where it is connected to a suitable part there-' of, such' as the manifold 33':

It will be observed that the helix 24 is considerably smaller than the sleeve 21, which heat from said helix by conduction is avoided.

The plug 30 is provided with a plurality of ports 31 extending vertically therethrough, some of these ports being outside and some inside of the hollow boss 29. Both sets of ports are covered by an annular valve plate 32, which normally rests upon the upper sur-- plate 32 is of magnetic ma:

sets of ports 31. lVh'en the plate 32 is thus raised, and'these ports open, it will be seen that air can flow upwardly through the outer ports into the tube 8 and thence downwardly through the inner ports into the hollow boss 29. The interior of this boss and the adjacent end of the tube 27 thus constitute a" carbureting or air mixing chamber in which the vapor issuing from thelower end 26 of the tube is mixed with air as fast as it flows out. It will be further notedthat the jet of vapor issuing from the lower end of the tube produces an injector action in the tube 27, which serves to draw air in through the ports 31, and the [mixture of air and vapor, which is stable and does not readily condense, isthen forced through the tube 28 into the engine manifold and cylinders, where it is readily ignited.

r Mounted on the upper end of the solenoid case is a block 34 of insulating material to the side of which is pivoted, by means of a screw 35, a switch lever 36, adapted to move into andout of engagement with a contact 37, also'carried by the block 34. The switch lever 36 is moved on its pivot by means of a pair of lugs or collars 39,-of insulating material, secured to a r6d 38, set into the upper end of thecore 6, and freely slidable through the head 2 of the solenoid casing. In order to cause the switch lever 36 to remain tem porarily in any position to which it may be moved, I apply to such lever a frictional drag by means of a spring 40, surrounding the screw 35, and bearing against the lever, as shown in Figure 3, It will be noted that the collars 39 are spaced apart a distance considerably greater than the width of the lever 36, so that there is a large amount of lost motion between the rod 38 and such lever. In other words, the lever is moved only toward the end of the stroke of the rod 38, in either direction.

My'improved fuel supplying device, as above described, is adapted to be used in connection with motor vehicles equipped with the usual storage battery and starting motor. The battery is indicated at 41, and

one side of it is grounded, as usual, as shown at 42. In order to render the'circuits easily traceable, I have also shown this same side of the battery as connected at 43 to the frame or casing of the solenoid.

'44 designates the usual starting switch,

and this is connected by means of a wire 45',

' with one terminal of the starting motor 46,

' 48 designates the usual ammeter,

the other'terminal of which is grounded.

and a wire 47 connects the ungrounded side of the battery through this amnieter with operated switch 49. This switch is arranged to selectively engage three contacts, 50, 51 and 52. The contacts 50 and 51 are connected by a wire 56, and a wire 53 extends therefrom to an insulated binding post 54, carried by'the boss 29. .A clip or connector 55 extends from the binding post 54 tothe lower end of the tube 24. i The other end of this helical tube is in electrical contact with the frame of the device, andis thus grounded.

l A wire 57 extends from the contact 52 to 35 and lever 36, whilethe other end of the solenoid winding is grounded on the frame, as by means of a spring terminal 61', engaging the head 2.

now be briefly described. hen it is desired to start the engine, the switch 49 is first swung over to the left into engagement with the contact 50. This establishes a circuit from the battery 41 through the ammeter 48, switch 49, contact 50, wire 53, binding post 54, connector 55, helical tube 24, to the frame of the device and thence back to the other side of the battery. The current flowing through this circuit will have the effect of strongly eating the tube 24. After the switch 49 has remained on the contact 50 for a few seconds,

it is swung over to the right, into a position where it simultaneously engages both contacts 51-and52. The contact 51 serves to maintain the circuit just traced, so that current continues to flow through the helical tube 24. At the same time, current flows from contact 52 through wire 57, and binding post 58, to contact 37, over lever 36 and wire to and through the winding of solenoid 5, from which it passes back to battery. This energizes the solenoid 5 and causes the core 6 to bedrawn upwardly. Just before the core reaches the upward limit of its stroke, the lower collar 39 engages under the switch lever 36 and swings it upward out of engagement with the contact 37, thus breaking the circuit through the solenoid and de-energizing the same. Immediately that the solenoid is deenergized, the spring 20 forces the core 6 down again, and before the lower limit is reached, the upper collar 39 vengages the switch lever 36v and swings it again into engagementwith the contact '37. This again energizes the solenoid and the cycle is repeated, the core 6 continuing to reciprocate as long as the circuit through contact 52 is closed. Thus, the pump piston? is moved up and down in the tube or barrel 8, and liquid fuel is drawn in through the pipe 12, and' forced down into and through .the heated helical tube 24. As the fuel passes through a manually this tube, it is not only vaporized, but super- The operation of my im roved device will heated to a high degree, and the hot vapor is discharged from the lower end 26 of'the tube .under considerable pressure, and in copious quantity.- The Valve plate 32 meanwhile havingbeen lifted by 'the 'magnetic effect of the current in the helical tube 24, air is drawn into the mixing chamber adjacent the nozzle 26 and thus mixed with the superheated vapor, the hot mixture being then forced through thetube 28 and delivered continuously to the, engine manifold; It will be noted that the ball 15 operates as a'check valve to prevent the backward flow of vapor,

and the pressure due to vaporization and superheating of the fuel is thus confined in the heating tube. This pressure causes the gasified fuel to be forcibly ejected from the lower end 26, of the tube, as above described.

Practicallysimultaneously with throwing the switch 49 into'engagement with the contacts 51 and 52 as described, the operator may depress the starting switch 44, thus causing the 'startin motor to crank the engine, Owing to t e abundant supplyof a warm, rich, non-condensing explosive mixture in the manifold, theengine will start immediately, and without thenecessity for pro-- longed operation of the starting motor.

While I have shown and describedonearrangement of circuits for operating my improved device, it is" obvious that other arran ements can be employed. One such. modified arrangement is illustrated in Figure.

7 2, in which, instead of the switch 49 andits associatedcontacts, I employ a switch 62 of the push button type, this switch. being connected withthe battery by wire, 63 and, when depressed, serving to establish connection between the battery and the wire 53. In this arrangement, the wire 57 is connected by a wire 64, with the wire leading to the start/- ing motor.

- he operation is as follows. When it is desired to start theengine, the operator first depresses'switch 62 for a brief interval of the wires 64 and 57. to the pump solenoid, the flow of current being maintained through the heating tube by continuing to hold down the switch 62. Thus,-the-tube isheated, the

' pump operated, and the starting motor set in ternal combustion engines comprising an motion at the same time, and the engine should immediately start. What I claim is Y 1. A fuel gasifying device for starting inelectrically conducting tube, means for passmg an electric current through said tube to heat the same, a connection at one end of the which the other end of said tube delivers,

means for connecting said chamber with the engine, and a valve operated by the magnetic flux set up by the current in said helical tube for controlling the, supply of air to said chamber.

3. A fuel gas'ifying device for starting internal combustion engines comprising a heater through which the fuel'is caused to pass, means independent of the engine and including an automatically operated shut off valve for mixing the vaporized fuel with air as soon as it issues from said heater, to prevent condensation thereof, and. means for delivering the mixture of fuel vapor and air to the engine.

4. A priming device for internal combustion engines comprising a tube, means for causing liquid fuel to flow into one end of the tube, means for'heating said tube to vaporize such fuel, means whereby the pressure due to vaporization is prevented from stopping the flow of fuel into said tube, and means for delivering to the engine the vaporized fuel forced from the other end of the tube by the pressure generated therein by vaporization. a

5. A priming device for internal combustion engines comprising a tube, means for heating said tube, a continuously operating. power actuated pump for positively, forcing liquid fuel into andthrough said tube and for building up an'eifective pressure to overcome the back pressure du'eto vaporization of the fuel in the tube and thus maintain a 'constant flow, and-means for delivering to the engine the vaporized fuel forced from device to vaporize the fuel, means for delivering the vaporized fuel to the engine, and means for simultaneously supplying current to both the heating device and pump.

7. Means for furnishing an explosive mixture to internal combustion engines at starting, comprising an electric heating device, a

Ill

reciprocating pump, a solenoid for continuously reciprocating said pump to positively force'fuel into and through said heating dey vice to vaporize the fuel, means for delivering to the engine the vaporized fuel issuing from said heating device, and means for simultaneously supplying said heating device and solenoid with current.

8. In starting mechanism for internal combustion engines, the combination with a starting motor, of an electric heating device, a reciprocating pump for supplying fuel into and forcing it through said heating device to vaporize the fuel, electromagnetic means for operating said pump, means for delivering to the engine the vaporized fuel issuing from said heating device, means for simultaneously supplying current to said starting motor, heating device and electromagnetic means, and independent means for supplying current to said heating device to warm it up before the motor is started.

9. Priming apparatus for internal combustion engines comprising a heating device, a pump for forcing liquid fuel into and through said heating device to supply an explosive mixture to the engine, said pump having the usual inlet and outlet valves, power means for continuously operating said pump as long as desired, and automatic means in addition to said valves, serving, when the operation of said pump is discontinued, to shut off the flow of liquid fuel to said heating device.

10. Starting apparatus for internal combustion engines comprising a heating device, means for supplying liquid fuel into said heating device, and means whereby the ex- I pansion of hot, gasified fuel issuing from said heating device will cause such fuel to enter the engine intake and cylinders under pressure, even before the engine begins to move.

11. A fuel gasifying device for starting internal combustion engines comprising a heater through which the fuel is caused to pass so as to be vaporized, an air mixing chamber into which the vaporized fuel is discharged as it issues from said heater, said air mixing chamber communicating with the engine, and

means controlled by the operation of said heater for governing the supply of air to said mixing chamber.

12. A fuel gaslfying device for starting internal combustion engines comprising a tube, means for heating said tube by means of an electric current, a connection at one end of the tube for supplying liquid fuel thereto, an air mixing chamber into which the other end of said tube delivers, means for connecting said chamber with the engine, and means operated by the flow of heating current for controlling the supply of air to said chamber.

In testimony whereof I affix my signature.

CHESTER L. BRISTOL. 

